CVE-2026-98854

Published Oct 18, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: of/overlay: only treat a positive changeset id as registered of_overlay_fdt_apply() stores the idr_alloc() return value in ovcs->id before checking it. On failure the stored id is negative, free_overlay_changeset()'s "if (ovcs->id)" check passes, idr_remove() is called with a negative id and list_del() runs on ovcs->ovcs_list, which is not initialized until after the id allocation. An allocation failure at that point dereferences NULL. Make free_overlay_changeset() treat only a strict-positive id as registered. The rest of the function already copes with a partially-initialized ovcs, so the error path stays a plain goto err_free_ovcs.

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References

Frequently Asked Questions

What is CVE-2026-98854? +
In the Linux kernel, the following vulnerability has been resolved: of/overlay: only treat a positive changeset id as registered of_overlay_fdt_apply() stores the idr_alloc() return value in ovcs->id before checking it. On failure the stored id is negative, free_overlay_changeset()'s "if (ovcs->id)" check passes, idr_remove() is called with a negative id and list_del() runs on ovcs->ovcs_list, which is not initialized until after the id allocation. An allocation failure at that point dereferences NULL. Make free_overlay_changeset() treat only a strict-positive id as registered. The rest of the function already copes with a partially-initialized ovcs, so the error path stays a plain goto err_free_ovcs.
How do I check if I'm vulnerable to CVE-2026-98854? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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